InvoicingInvoice requirements in Germany: the § 14 UStG checklist
The 10 mandatory details under § 14 (4) of the German VAT Act with an example, small-amount invoices up to €250, what counts as an e-invoice since 2025, and the most common mistakes.
Guides
Invoices, reminders, receipts: done right
How-tos with copy-ready templates, checked for Germany and Austria.
74 guides · updated 04/11/2026
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Writing invoices9
Invoicing
InvoicingInvoice requirements in Austria: the § 11 UStG checklist
What an Austrian invoice must show: the nine details under § 11 UStG, your client's VAT ID above €10,000, small-amount invoices up to €400, and the special cases that trip people up.
InvoicingInvoice numbers: what the rules in Austria and Germany say
Sequential, unique, not necessarily gap-free: what Austrian and German law says about invoice numbers, with formats, number series, and what to do when you cancel an invoice.
Tax & VATSmall-business invoice in Austria: that's how it's done
The sentence most people copy — "Gemäß § 19 UStG wird keine Umsatzsteuer berechnet" — no longer matches the law precisely!
Tax & VATReverse-charge invoice in Germany: that's how it's done
A § 13b invoice shows no VAT and must carry the German sentence „Steuerschuldnerschaft des Leistungsempfängers“ verbatim (§ 14a Abs. 5 UStG). More important than the sentence is the question nearly every template skips.
InvoicingInvoicing a client in Austria from Germany: reverse charge, VAT numbers and the EC Sales List
Invoicing an Austrian client from Germany: what the reverse-charge invoice needs, which VAT numbers to show, what applies to small businesses and when e-invoicing is required.
- Invoicing
Invoicing a client in Belgium: reverse charge and what the Peppol mandate means for you
Invoicing a Belgian client from Germany or Austria: which note goes on the invoice, which number your client needs and whether Belgian e-invoicing since 2026 applies to you.
- Invoicing
Invoicing a client in France: reverse charge, autoliquidation and e-invoicing from 2026
Invoicing a French client from Germany or Austria: which note goes on the invoice, what « Autoliquidation » means and what the French e-invoicing reform from September 2026 changes for you.
- Invoicing
Invoicing a client in the UK from Germany or Austria
What goes on an invoice to a UK client when you are based in Germany or Austria: no German or Austrian VAT, the right place of supply note, and what changes for private customers.
Payment reminders and late interest3
Payment remindersPayment reminders and dunning: three steps with templates
One reminder after the due date is enough for default. When an Austrian or German client is in default, three templates, the €40 flat fee and German terms.
Payment remindersCalculating late-payment interest in Austria and Germany
Late-payment interest 2026: Germany 10.52 % (B2B) or 6.52 %, Austria 10.73 % (B2B) or 4 %. The formula, a worked example, the €40 flat fee and a template.
- Payment reminders
Payment reminders in English: templates for first, second and final notice
German dunning has three escalating stages and English has no single word for it. Three templates to copy — payment reminder, second reminder, final notice.
Reminders abroad, by country43 countries
Pick your client's country: English reminder templates and tips for that country.
- Austria
- Belgium
- Bulgaria
- Croatia
- Cyprus
- Czechia
- Denmark
- Estonia
- Finland
- France
- Germany
- Greece
- Hungary
- Ireland
- Italy
- Latvia
- Lithuania
- Luxembourg
- Malta
- Netherlands
- Poland
- Portugal
- Romania
- Slovakia
- Slovenia
- Spain
- Sweden
Receipts and bookkeeping2
BookkeepingA monthly receipt routine your bookkeeper will thank you for
Collect, match and hand over receipts once a month: a 30-minute routine in five steps, what counts as a receipt, and what to do when one is missing.
BookkeepingElectronic cash receipts in Austria from 1 October 2026: what changes
From 1 October 2026 a receipt in Austria counts as issued when the customer can read it on a screen on the spot. That is not a new obligation — and if you only invoice by bank transfer it does not apply to you at all.
AI in the back office16
Open the AI back office overview
AI & automationHow AI agents are changing back-office work for small businesses
AI agents handle the office routine and you approve: less typing, faster admin and new roles in a small team. How freelancers and small businesses put the agentic back office to work.
AI & automationAI assistants in 2026, explained: ChatGPT, Claude, Gemini, Copilot and Grok
An overview as of 08/10/2026: what ChatGPT, Claude, Gemini, Microsoft Copilot and Grok are for, what agents, MCP and skills mean, and how a small business in DE or AT can choose.
AI & automationBookkeeping and AI: how working together changes in DE and AT
The way small businesses, their bookkeeper and their tax adviser work together is changing: how AI agents are shaping the future of running a business in Germany and Austria.
AI & automationAI agents, MCP and skills: the terms explained
Agent, connector, skills, MCP: the AI terms of 2026 in plain words, so AI speeds up your back office. Plus approval, prompt injection and more, each with what it means in Germany and Austria.
AI & automationAgentic back office: how AI agents take over your admin
What an agentic back office is, which admin AI agents already handle for you and how to get from chat to agent. AI prepares, you approve, and you win back time for the work that matters.
AI & automationAI for admin: 7 tasks to hand to ChatGPT or Claude first
Seven safe first admin tasks for ChatGPT or Claude: emails, reminders, quotes, checklists. With a neutral tool comparison and a prompt you can copy.
AI & automationAI and GDPR: when ChatGPT and Claude are an option for client data
When client data in ChatGPT or Claude is an option, which plans offer a DPA and no training, what DE and AT add, and what GoBD and AI Act Art. 4 ask of you.
AI & automationAI for invoicing, time and dunning: from hours to paid
Can AI write a valid invoice in Germany and Austria? Yes, as a draft you check. How hours become an invoice, how AI writes reminders and what stays a rule.
AI & automationAI for bookkeeping prep: receipts, month-end and VAT period
Let AI read your receipts, prepare the month-end in about 20 minutes and line up the UStVA (DE) or UVA (AT). What it does well, what you check, what your adviser needs.
AI & automationAI skills for the back office: teach AI your way of working
What an AI skill is, how it differs from a prompt, where skills work today (as of 08/10/2026) and which back-office routines make good ones.
AI & automationAI agents for small businesses: connectors, MCP and what they can do
What makes an AI assistant an agent, how connectors and MCP work, what an agent can do in your back office and which ChatGPT and Claude plans allow it (as of 08/10/2026).
Billy, our AI ghostDelegate admin to AI safely: reviews, approvals, permissions
Which admin steps AI can prepare, which need your OK, how to review a draft, set permissions and fix a mistake in DE and AT. And how it feels day to day.
AI & automationWhat is MCP?
MCP explained simply: how AI apps like ChatGPT and Claude reach Backbone safely, what they may do and what stays off limits.
AI & automationConnect Backbone to ChatGPT
Connect ChatGPT to Backbone: turn on developer mode, add the MCP address, sign in and approve. Then log time and draft invoices from the chat.
AI & automationConnect Backbone to Claude
Connect Claude to Backbone: copy the MCP address, add it as a connector, approve. Then log time and draft invoices from the chat.
Billy, our AI ghostAI in dunning: the future of the back office
AI can watch due dates, draft reminder text and send each stage on schedule. Automation with AI agents is the future of the back office.
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